http://www.atf.treas.gov/firearms/st...washington.pdf
That is the current law set for Washington state according to the ATF. It mentions no restrictions on how much ammo you can have.
The gun grabbers (juden hate armed goys) are known to use other sections of law against lawful gun owners. It may be part of the fire code, haz-mat code or even in the laws that decide who is part of an "illegal" militia.